Automatic telephone system



April 12; 1927.

A. J. RAY ET AL AUTOMATIC TELEPHONE SYSTEM T. Ha an ---Harh'afT Filed Jan. 11, 1921 Elf Thur Jfiag-FraJ April 12,1927" mmwm A. J. RAY ET AL AUTOMATIC TELEPHONE SYSTEM Filed Jan. ll. 1921 5 Sheets-Sheet 2 v Immfifihur Jfisy-Frad IMscfsaw-Herbfifi UbErgEU April 12 9 1927.. Q 1 ,624,007

A. JPRAY ET AL AUTOMATIC TELEPHONE SYSTEM Filed'Jan. 11, 1921 s Sheets-Sheet 3' T; 7 Hi1 hur J. H e b-Fred Hadsan fiar'biff I"? Ulwggfll Patented Apr. TE, 1927.

NEE SATES 5- ARTHUR 3'. BAY, OF GHICAGO, ILLII IOIS; FREE) llllii lliifililil, 0H BAY, W'TSCOH- SEN; Alli) HERBERT F. OBEBCi-EELL, OF EIVLEE, FDR-EST, ILLINOIS, 'aSSIG-BTORS, BY

MESNE ASSIGNMENTS, TO AUTOEEATIC ELECTTLEC ENG, OF CTalICAG'O, lLLlElt-OIS, A

CUZRQPORATION 01E DELAVTARJE.

AUTOMATIC TELEFHQEE Application filed January 11, 1921. serial Ito. 436,559.

The present invention relates in general to automatic telephone systems, but is more particularly concerned with automatic telephone systems of the kind which are generally installed in small towns or villages, these systems being commonly known as mixed service systems, or community automatic exchanges. Reference is made here to the U. S. patent to Willis, No. 1318,00 5 issued Oct. 7, 1919, on which this invention is an i in p rov ement.

The system herein described provides for giving local service to private or individual line subscribers and to rural or party line r subscribers, and also provides means whereby such subscribers are given access to trunk lines extending either to an automatic exchange or to a manual exchange or both, one of the objects of the invention being the provision of an improved automatic connector switch for taking care of the diiferent kinds of service named.

A further objectof the invention is to provide a new and improved method of selectively signalling a large number of subscribers on a rural party line.

These and other objects of the invention will appear fully hereinafter.

Referring now to the drawings:

In Fig. l is shown an ordinarv automatic substation A having a rotary lineswitch C individual thereto. The lineswiteh C is of the well known rotary type, with its wipers moving in a forward direction only and having no normal position, and has the function of extending the line of substation A, when the receiver is removed, to a trunk line terminating in an idle mixed service connector.

These connectors are of the usual Strowger vertical and rotary type and have access to individual and party lines and also to trunk lines. One of these connectors is shown at H in the drawings. Associated with this connector are four minor switches l, J, K, and L, Fig. 2, which are simple rotary switches adapted to be rotated in response to impulses and restored to normal by the operation of their respective release magnets. At M in Fig. 53 is shown a code ringing machine which is common to the exchange, and which consists of a revolving drum having rows of metal contacts on it which are adapted to be engaged by a number of wipers 22'5-281, inclusive. Around the outside of the drum are a number of projections which are arranged so as to enthe spring 297 and move tact at regular intervals with the contact 280. This operation serves to ground the several rows of contacts on the drum. These projections are so placed that the ground is removed from the contacts while the brushes are still in engagement with them, which of course prevents the sparking which would otherwise occur were the brushes to make and break their own connections.

@ne of the individual lines to which the connector H has access is shown in Fig. 6, and one of the rural or party lines in Fig. 5.

Two trunk lines going to other enchanges are shown in Figs. 3 and i, the one in Fig. at, being a manual trunk terminating in a ring down signal and a jack, and the one in Fig. 3 being an automatic trunk line including a repeater of ordinary two wire construction.

Having briefly set forth and described the apparatus shown in the drawings, the operation of the system will now be described. For this purpose it will be assumed in the first case that an automatic private line subscriber at substation A desires to call the subscriber at substation A. When the calling subscriber removes his receiver a circuit is completed over the line conductors 11 and 12 for the line relay 14 of the lineswitch C. Upon energizing, the line relay completes a circuit extending through the switching r-elay l8 and the stepping magnet 15 in series at its armature 20, and at its armature 19 connects the test wiper 26 to the above circuit at a point midway between the switching relay and the said stepping magnet. The operation now depends upon whether the test contact with ivhich the test wiper 26 is in engagement is or is not busy. if this test contact is busy it will have ground potential upon it, the switching relay 13 will be short circuited, and the stepping magnet 15, which interrupt-s its own circuit, will operate as a buzzer to advance the switch wipers 25427, inclusive, in search of an idle trunk line. This operation will continue as long as the test wiper 26 engages busy or grounded test contacts. However, we

it into 0011- may assume that in the present case when the call is initiated the connector H is idle and the test contact 31 thereof is not grounded. Under these circumstances when the line relay 14 is energized, the switching relay 13 is energized immediately afterwards, with the result that the line conductors 11 and 12 are disconnected from the Winding of the line relay 1 1 and from ground, respectively, and are extended by means of armatures 16 and 17, wipers 25, and 27, bank contacts 80 and 32, normally closed spring contacts controlled'by relay 50, armatures and 71, and through the upper and lower windings of the line relay 52 of the connector H to battery and ground, respectively. Immediately upon the extension of the line as above described the linerelay 52 energizes and closes the circuit of the slow acting release relay 53. Upon energizing, relay 53 prepares the circuit of the switch for operation in the usual manner, at its armature 80, and at armature 79 completes a holding circuit extending back to the lineswitch C over the following path: ground G working contact of armature 79 and the said armature, release trunk conductor 7 9, test contact 31, test wiper 26, armature l7 and its front contact, winding of switching relay 13, and the winding of the stepping magnet 15 to battery. It is understood that the above circuit is established before the slow acting line relay 14 has had time to deenergize. By a ground potential on the test contact 31 and its multiples this holding circuit also serves to render the connector H busy to other lineswitches, and the busy potential also extends by way of the private normal conductor 34 to multiple test contacts in the banks of all the connector switches, thereby protecting the line from intrusion in a well known manner.

Returning new to the operation of the connector H, when the subscriber at substation A operates his calling device S for the first digit of the desired number a series of interruptions are produced in the circuit of the line relay 52 which operates in response thereto and at each retraction of its armature 77 completes a circuit extending from ground G, back contact and armature 68, armature 77 and its back contact, armature 80 and its front contact, winding of slow acting relay 54L, armature 104 and its back contact, armature 96 and its back contact, winding of the vertical magnet 126, conductor 18G, first contact and wiper 267 of the minor switch J to battery. By the operation of the vertical magnet 126 the wipers 135 138, inclusive, are raised step by step until they stand opposite the level of bank contacts in which is located the set of cont acts associated with the line of the substation A. The slow acting series relay 54; which is energized in series with the vertical magnet, mantains its armature attracted throughout the vertical movement of the switch. Upon the first vertical inoveniient oi the switch, the oil normal springs 82 and 853 are shifted into their alternate position and a circuit is thereby con'ipleted extending as follows: ground G oil normal springs 83, armature 113 and its back contact, arnuiturc 86 and its front contact, and through the winding of the slow acting relay 59 to but tery. Relay is energized and being slow acting maintains its arnnitures attracted for a short interval after the deenergization of the slow acting series relay 51, which re tracts its armatures an instant after he tcrmination of the vertical movement of the switch. An impulse of current then sent from ground G, springs 83, armature 113 and its back contact, armature S6 and its back contact, armature 116 and its front contact, back contact of armature 102 and the said armature, back contact and aru'iature 9%, conductor 181, and thence through the winding of the rotary magnet 252 of the minor switch J to battery. On energizing magnet 252 rotates the wipers 267 and 268 of; the minor switch into engagement with the second set of bank contacts.

The subscriber at substation A, may now operate his calling device in accordance with the second and in this case the final digit oi the desired number. before, a eerie oi interruptions is produced in the line circuit to which the line relay again responds by trai c sitting a series of impulses to the retary magnet 127 over the following path: ground G, baclr contact and armature (3S, armature 77 and its back contact, arn'iature 80 and its front contact, through the winding of the slow acting series relay 5%, armature 104 and its back contact, armature 96 and its back contact, through the winding oi the rotary magnet 127, conductor 185, second contact engaged by wiper 267 and the said wiper to battery. Responsive to there impulses the rotary magnet is operated to rotate the switch wipers into engagement with the particular set of bank contacts in which the line of substation A terminates, these bank contacts being indicated in the drawing by the reference numerals 150, 151, 152, and 153. As before, the slow acting relay 51 is energized in series with the rotary magnet and completes the circuitof the slow acting relay After the operation of the rotary magnet 127, the slow acting reay fiat dcencrgizes. Relay 59 also prepares a testing cir cuit which is effective if the line of the subscriber at sul'istatiou A is busy. Supposing this to be the case, a ground potential will be present on the test contact engaged by the test wiper 137. A circuit is thereby completed extending as follows: from the said grounded test contact. test wiper 137, conductor 1.96, contact engaged by wiper 266 andthe said wiper, conductor 180, armature (S6 and its baclr co1n':act, armature 85 and its bacl: contact, armature 117 and its front contact, back contact and armature 98, and thence through the winding of the test relay 5? to battery. Upon energizing the test relay establishes a locking circuit for itself at armature 105, and at arn iature 106 connects a lead from the busy mac-nine to the lower heavy talking conductor. By this means the calling an ribcr is given an audible busy ml, and adiised thereby that the desired line is or the time being inaccessible, he will hang up his receiver.

:l-lavlng described the operations which take place when the called line is busy, it will now be assumed that the line is idle when the connection is attempted. Under these circumstances, when the test wiper 13''? comes into engagement with the ungrounded test contact- 152, the test relay will not be energizes'l. lhcn when the slow acting relay deeuergizes at the end or the rotary movement of the switch, an impulse of cur rent is again sent to stepping magnet 252 of the finder switch it to step the wipers 2'67 and 268 into engagement with too third set of banlr contacts. A circuit will be completed for the switching relay 56 extending as follows: from the grounded release trunk conductor Z9, armature 105 and its back contact, through the lower winding of the switching relay 56, back contact and armature 1.1T, baclr contact and armature back contact and armature 66, conductor 180, wiper 266 and contact engaged thereby, conductor 196, test wiper 137, test contact 152, conductor 1'76, winding of the switching relay let and then through the winding of the stepping magnet 15 to battery. Upon the closure of the above traced circuit, relays and 1d energize in series, and the latter relay is operated to clear the line of the substation A of its normal battery and ground connections in, the line switch C It is noted that relay 14 is operated only about half way, due to a mechanical in terlocking device controlled by the line relay 16, which was not operated, and relay 141 does not therefore extend the line conductors through to its wipers. At the connector ll, when the switching relay 56 en ergizes, the said relay establishes a locking circuit for itself at its armature 05, connects direct ground to the test Wiper 137' at armature 97, opens the operating circuit of the minor switches associated with the connector at armature 96, and at air-matures 9d and 100 completes the ringing circuit for the called subscribers telephone A. Ringing current flows from the generator V, first contact and wiper 22 0, conductor 189,, back contact and armature 91, armature 100 and its front contact. back contact and armature 69.

wiper 13.1, bank contact engaged thereby and thence over the lower line conductor 17 i, ringer and condenser of the substation A, back over the upper line conductor 172, bani; contact 150, wiper 135, armature 65 and its back contact, armature 87 and its baclr contact armature 109 and its baclr contact, lower winding of ring cut oil relay 55, trout contact and armature 9d, conductor 184;, and then through the winding of the stepping magnet to battery. lilagnet 252 does not receive enough current to energizeaud relay 553 is so constructed that it does not respond to alternating current. As the drum of the r ngingniachine li l rotates, the brush 281 ongages the contact 287, and similar contacts, each time completing the circuit of relay 101 from the grounded contacts. As the contact 287 and similar contacts are equally spaced on the drum, this serves to interrupt the circuit for relay 101 at regular intervals, which operates to intermittently apply ring current to the above traced ringing c cuit. Now when the called subscriber at substation A answers, the ring cut off relay will energize, a path for direct current being provided through the transmitter and receiver oi the called substation. Upon energizing, relay 55 establishes a locking circuit for itself at armature 89, opens the ringing circuit at armatures 87 and 91, and at the working contacts o1 these armatures finally completes the talking connection.

The desired connection has now been es-- tablished. The transmitter at the called substation A is supplied with talking current from the windings of the back bridge relay 51 which energizes and in the usual manner reverses the battery back to the calling subscriber who is supplied talking current from the windings of the line relay 52. The voice currents take the path shown in heavy lines which will be understood without further explanation.

ll hen the subscribers are through talking they will both replace their receivers. The replacement oil the receiver at substation A causes the lineswitch C and the connector H to be released in the following manner: l i hen the line circuit of the line relay 52 is broken by the replacement of the receiver,

the line and release relays 52 and 53 are both deeuergized, and a circuit is completed for the release magnet 128, extending from ground G, back contact and armature 68, armature 77 and its back contact, armature 80 and its back contact, ottl' normal springs 82, baclr contact and armature 112, and through winding oi. the release magnet 128 to battery. li iagnet operates to restore the connector ll to normal and at the same tin'ae places ground on conductor 198 which elrtends through the winding oi" the release magnet of the minor switch J to battery. Release magnets 288 and 261 of the minor switches I and K were energized. in

multiple with the release magnet 128 of the connector H but since neither switch has been operated the energization of these magnets is without eii'ect. The lineswitch C restored to normal upon the deenergization of the release relay 53, ground being then removed "from the holding circuit of relay 13. It will be noticed that an auxiliary release circuit is completed for the release magnets 128, 288, and 261 in multiple with the one above traced extending from ground G, back contact and armature 68, armature 77, armature and its back contact, conductor 179, contact engaged by wiper 268 andthe said wiper, conductor 195, back contact and armature 112, and thence through the winding of release magnets 128, 288 and 261. Thus the circuit of the release magnets of the various minor switches will not be opened when the connector H is restored to normal but rather when the minor switch J- reaches normal thereby giving ample time for the release of all the switches.

The process oi setting up a local connection when a private or individual line is called having been above explained, the manner in which a party line subscriber is called will now be described. All party line subscribers have four digit numbers and as before stated respond to code rings. The code ring or a particular station on a party line corresponds to the last two digits of that party line subscribers number. For instance, let us suppose that the telephone number at substation A is number 2631, in which case the subscriber will respond to the code: 3 short rings, pause, 1 short ring.

When the subscriber at substation A takes cit his receiver preparatory to making the call, a circuit is completed for the line relay 14 of the lineswitch G in the usual manner over the line conductors 11 and 12 in series. Upon energizing, the line relay 14L closes at its armature 20 a circuit which includes the switching relay 13 and the stepping magnet 15 in series, and at its armature 19 connects the test wiper 26 to a point midway between the switching relay and the said stepping magnet. The operation now depends upon whether the trunk line with which the wipers 25-27, inclusive, are associated is busy or idle. If busy a ground potential will be present on the test contact engaged by the test wiper 26. The switching relay will therefore be short circuited and the stepping magnet 15 being supplied with direct ground will operate as a buzzer to advance the wipers 2527, inclusive, step-by-step in search of an idle trunl: line. It will be as sumed, however, that the trunk line with which the wipers of the lineswitch C were associated with when a call was initiated is the trunk line shown in the drawings and is idle at this time. Under these conditions, upon the line relay 1 1 energizing, the switching relay, being no longer short circuited, will energize immediately aij'tcrwards in series with the stepping magnet 1:). its resuit of the energization of the switching rolay, the line conductors 11 and 12 are disconnected from the winding of the line relay l i and from ground, respectively, and tended by way of urmaturcs 1(3 and 1.8 and their working contacts, wipers an and 27, bank contacts 30 and 32, normally closed contact springs controlled by relay 510, armatures 70 and 71 and their resting contacts to the upper and lower windings ot the line relay 52 of the connector H. As before described the line relay 52 on energizing com pletes the circuit of the slow acting relay )3 which upon attracting its armature prepares the operating circuits of the connector ll and at the same time establishes a, holding circuit for the switching relay 1% of the lineswitch The calling subscriber may now operate his callirn device bl in accmrdance with the first digit of the desired number thereby producing a series of interruptions in the line circuit or the line relay 52. The line relay operates in the usual numner sends ing a corresponding series of impulses to the vertical. magnet 126 in series with the slow acting relay Magnet 1% operates to raise the wipers 135438, inclusive, slepby-step until they are placed opposite the second level of bank contacts in which the desired party line is located. The slow acting series relay 54L energizes in series with the vertical magnet thereby com gilcting the circuit of the slow acting relay 59. Upon the deenergization of the series relay, an impulse of current is sent from ground G, oil normal springs 83, armature 11.3 and its back contact, armature 86 and its back contact, armature 116 and its t'ront contact, back contact and armature 102, back contact and armature 94L, conductor 184., and through the winding of the rotary or stopping magnet of the minor switch to battery. hflagnot 252 operates to step the wipers 267 and 26%) onto the second set oi bank contacts. \Vhcn the subscriber at substation A operates his calling device for the second digit another series of interruptions is produced in the circuit of the line relay 52 which operates in. response thereto, this time sending a corresponding series of impulses to the rotary magnet 127. The slow acting series relay 5 L energizes in series with the rotary magnet 127 and again completes the circuit of relay 59. As before, when relay 54L dccncrgizcs, following the cessation oi? impulses to the rotary magnet, an impulse oi current sent to the stepping magnet 252 of the minor switch J which advances the wipers 2G7 and 268 into engagement with the third set of bank contacts. Magnet 127 operates to rotate the wipers 135-138, inclusive, on to the sixth set of bank contacts in which termiiltl lltl

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' net 251 of minor switch 1 hates the desired party line and which, as shown in the drawings, are the bank contacts 155, 156, 157, and 156. It will be seen that the private normal conductor 173 of the lineswitch C t1"l1'1l1121t$5 in the bank contacts engaged by the test wiper 136. Therefore it" the party line, upon which the sub: scriber at substation A is located, should happen to be busy, at ground potential will be present on the bank contact 156. However, this will have no etlect at the presenttime. The calling subscriber will now opcrate his calling device for the digit 3, this being the third digit in the number 01' the subscriber at substation 223. At each retraction of its arn'iature, the line relay 52 sends an impulse of current over the following path: ground G", back contact and armature 66, armature 77 and its baclr contact, armature 80 and its front contact, winding of slow acting relay 5%, armature 104- and its back contact, arn'iature 96 and its back contact conductor 187, winding of magnet 25 1, contact engaged by wiper 267 and the said wiper to battery. Magnet 254: responds to these ii'npulses and steps the wipers 269 and 270 on to the fourth set of bank contacts in the minor switch K. By the operation of the slow actin relays 5 1 and 59, the step ping magnet 2T2 of the minor switch 5 is again energized and the wipers 267 and 268 are rotated into engagement with the fourth set of bank contacts. The calling subscriber may now send the last digit of the desired number which in this case is the digit 1. The line relay operates as before and sends one impulse of current to the stepping magover a circuit extending from ground G, armature 68, armature 77 and its back contact, armature 80 and its front contact, winding or the slow acting relay 54-, armature a and its back contact, armature 96 and its back contact, conductor 167, winding of magnet 251, wiper 267 in the fourth position to battery. Magnet 251 operates to step the wipers 265 and 266 of the minor switch I into their second position. As before, the series relay 5-1 and also the slow acting relay 59 are energized and an impulse of current is again sent to the stepping magnet 252 of the minor switch d thereby stepping the wipers 267 and 268 into their ii'l'th position. As before stated, when this line is busy, a ground potential will be present on the bank contact 156 engaged by the test wiper 136. Assuming this to be the case, then before the slow acting relay has eenergized a circuit may be traced from the said grounded test contact, test wiper 136, conductor 191, bank contact engaged by wiper 266 and the said wiper, conductor 180, armature 66 ad its back contact, armature 85 and its back contact, armature 117 and its front contact,

7 back contact and armature 98, and through back contact and the winding of the test relay 57 to battery. Upon energizing relay 57 establishes a locking circuit for itself at armature 105 and applies the busy tone at armature 106 to the lower heavy talking conductor. When the calling subscriber hears this tone, he will know that for the present the line of the subscriber at substation A is inaccessible and he will replace his receiver, thereby causing the release of the connector and its associated minor switches to be released in the manner hereinbelore described.

Having described the operation of the connector H and its associated apparatus when the line of the called subscriber at substation A was busy, it will now be assumed that the line 01 the subscriber at substation A Was idle when the connection thereto was attempted. Under these conditions no ground will be present on the test contact 156 and following the deenergization of the slow acting relay 59, a circuit may be traced over the following path: ground on release trunk conductor 92, armature 105 and its back contact, lower winding of switching relay 56, back contact and armature 117, back contact and ari'nature 85, back Contact and armature 66, conductor 180, wiper 266 and the second bank contact, conductor 191, test wiper 136, bank contact 156, private normal conductor 173, winding of switching relay 141: and the winding of the stepping magnet to battery. Relays 56 and 14 operate over this circuit. However, due to a mechanical device controlled by the line relay 16 the relay 14 operates only far enough to clear the line conductors of their normal battery and ground connections. Upon ei'iergizing, relay 56 establishes a locking circuit for itself atarmature 95, opens the operating circuits of the minor switch I at armature 96, places ground on the test wiper 136 at armature 97 in order to protect the line of the subscriber at substation A from intrusion, and also prepares the ringing circuit for the subscriber at substation A lVhen the switch ing relay 56 energizes, a tone from the tone machine T flows over the following circuit: tone machine '1", conductor 199, back contact and armature 121, conductor 197, fourth contact and wiper 270, conductor 182, back contact and armature 91, armature 100 and its front contact, back contact and armature 69, wiper 138 and thence over the party line on which the substation A is located. This tone will be audible to any subscriber on the party line should he remove his receiver during a silent period between code rings informing him that the line is in use and he will therefore replace his receiver upon the switchhook. The ring will not be cut oft at this time for the reason that upon removing the receiver it rises only far enough to close the springs similar to 267 and 289 on account of the stop 286, and the subscribers receiver will be connected across the line through a condenser enabling him to know whether the line is or is not busy at this time without disturbing any of the operations.

It will be seen that the brushes 2?? and 270 of the ringing; interrupter M were selected. by the last two digits called. Therefore, upon the termination of the last impulse and when the brush 27'? engages the grounded contact a. circuit is completed extending as follows: grounded contact 285, brush 27?, contact and wiper of theininor h K, conductor 181, back contact and ature 90, conductor 182-}, first contact and per 272 of the minor switch L, winding pping magnet contact engaged by and the said wiper to battery. J t 253 operates to step the wipers 2Y1 one step and atthe same time closes at springs 286 a locking circuit for itsell which extends to the spring 280 which was grounded at the same time the contact 285 was grounded. lhereifore the stepping magnet remains energized until the drum otthe interrupter M rotates enough to al low the spring 297 to break contact with the spring 280. ll hen the wipers 271 and 272 are rotated one step, a circuit is completed extending as follows: ground G oft normal springs 83, conductor 19 1, wiper 271, conductor 190, and through the winding of relay 58 to battery. Upon energizing, relay 58 prepares the circuit for the ringing relay 60 wh ch is energized intermittently by the operation of the interrupter M over the following circuit: grounded contacts 200 and 291, etc, brush 280, conductor 189, front contact and armature 111, and thence through the wil'iding of relay 60 to battery. Relay 60, on energizing, completes the ringing circuit which extends from the ungrounded pole of generator V by way of front contact and armature 121, conductor 10?, contact engaged by the wiper 2'70 and the said wiper, conductor 182, back contact and armature 91, armature 100 and its front contact, back contact and armature 69, wiper 138, bank contact 1'18, conductor ii"? and thence over the party line on which the subscriber at substation A is located through the ringers and condensers of the substations on the said party line, conductor 175, bank contact 155, wiper 135, armature and its back contact, armature 8? and its back contact, armature 109 and its front contact, and thence to ground on release trunk conductor 93. Relay 60 momentarily energized each time one of the contacts 290, 29. and 202 passes under the brush 280, after which there is an interval, determined by the space between contact and the next contact 293, during which relay 60 noes not energize. This space is provided for the purpose of giving the usual interval between successive rings in the same code.

During the above mentioned interval, con- Leases";

tact 29: is moved into engagement with he corresfioiuling brush 27:), whereupon a circuit is again completed tor the stepping; map, not 2:12? by no}; oil the second contact in the bank ol wiper 2T2 and saiil wiper. lll agrucl .353 thereupon operates as before and stops the wipers 271. and 2T2 of the minor switch L into engagement with the third set ot' bani: contacts. This operation occurs, it will be noted, during the silent period between two successive rings, and its result is that the wiper 2T2 is connected up with the slop wiper 205 01'' the switch i. so as to enable the second ring to be terminated, as will be explained, subseipien tly.

[it the end ot the space between succcs siye rings or just alter the wipers ill. and 2'2'2 ot the switch ll have been advanced into engagement with their third set oi bani; coin "1;, the contact 2923 passes under the brush 280, thereby giving one short ringr in the above described manner. it will, thus be seen that the code 8 short rings, pause, 1 short ring has been transmitted to the party line on which the subscriber at substation it is located. li hen the brush 2% cup": cs contact 297, a circuit is completed cnteudinu' from grounded contact 207 by way of brush 27?, contact engaged by wiper 205i and the said wiper, wiper in its third position, winding of the stepping magnet i353, and wiper 267 in its li'lfth position to battery. Magnet 253 operates as bcliore to ad since the wipers 271 and 2142 into their :lourth posh tion thereby brealrinp; the circuit ot relay as which immediately dceuer gixes opening the circuit to the ringing r lay 10 at armature 111. When the brush 3 engages; grounded contact magnet 25?) is again cnor rbaeil and steps the wipers and 22 into their fifth position thereby completing a. circuit which extends as :tollows ground P", oli normal springs 83, conductor 191. wiper :l i'l. conductor 198, and thence through the winding oi the slow acting;- relay 5!) to battery. Upon energizing relay 5.50 con'ipleles a circuit extending from groom. Cl. oli' nor-om. springs 83, armature 11 -3), and its baclr contact, armature and its bitch: contact, arena-- ture 110 and its front contact, coiuluctoi- 35313. and thence through the winding: oi? the release magnet 260 of the minor switch ll to battery. llhignet 200 operates to re: ore the wipers 271 and into their lirst or initial position.

The lay out 01" all contacts on the drum ol the ringing interrupter it is shown in be drawing, and hence the ringing]; opc'ira-i on will start in before described upon .lio lnush 27? again cuuagiu the contact .2 5' the minor switch L being now in its normal position, and therctorc the code rin oi? th subscriber at substation it will an; in sari as above explained. iilhould the subscriber at substation A upon hearing his code call th I lllU

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lilll weapon? remove his receiver in the middle of the code the ringing will continue until the code is finished because the relay is locked energized while the code is being rung and its operation opens the circuit of the ring out off relay 55 at armature 109. It will be noticed that the release magnet circuit is opened at armature 112 by the operation of relay 58. Therefore, should the calling subscriber at substation A hang up at this time, the connector will not be released until the complete code has been rung. It is true that an i1npulse of current may be sent to the release magnet when the circuit for the line re lay 52 is broken but this is ineil jective for the reason. that it flows through the resistance R and magnets 128, 288, and 261 do not receive enough current to energize.

l Vhcn the code is finished relay 58 deenerand if the receiver of the substation A is removed and the trip 288 is moved to llow the receiver hook to engage both upper contacts, direct current will low over a circuit extending from ground G on ccndoctor 199 by way of back contact and :U.'1"l'1fl ture 123i, conductor 197', Wiper 270 in its fourth position, conductor 182, bacl; contact an nature 9i, arn'iature 100 and it tr-"mt co ict, back contact and armature ($9, wiper 13S, bani; contact 158, conductor 1T7, through the switchhooh springs transmitter and primary winding of the induction coil (it the substation A conductor 1T5, bani; contact l 135, arn'iature l5 and its be it co armature and bacl; contact, arn'iature 109 and bacl: contact, lmvcr winding of ring out off relay, front contact and armature 9t, conductor 18%, winding of magnet to battery. Relay wl ile it 7 not respond to alternating current, gizes over this circuit Upon 'iscing, relay 55 locks itself energized at armsture 5 9, and at arinatures Eli and 9t opens the ringing circuit, and at the front contacts of these armatures completes the circuit for the back bridge relay 51. This latter relay operates before described to reverse the battery over the line of the calling subscriber at substation A for any well known purpose. Relay on energizing also opens the initial operating circuit of the minor switch L. Convcrsati on may now be carrier on between the subscribers at substations and battery being supplied to t. callin sub :riber from the line relay b2 and to the caller. subscriber from the back bridge rel hen the conversation is terminated of the connector and its asscciin d inn" switches takes place in a manner hei e- 1 described upon the subscribe:

l i S rlaving described hoi' both party and ght line connections are set up, let us .,onsider the operation of the connector H when a calling subscriber desires to call a manual subscriber in a neighboring exchange. The subscriber at the substation A who desires to connect with the manual exchange will therefore remove his receiver and operate his calling device S in accordance with the digits 91. d hen the receiver is removed the lineswitch C operates as before described to extend the associated line to a trunk line terminating in an idle connector which we will assume is connector H. When the connection is thus extended, the line release relays 52 and 53 are energized as previously described and with the same results. Whcn the calling device is oper ated the switch wipers 135-438, inclusive, are raised step by step by the vertical magnet 126 under control of the line relay 52 and are brought to rest opposite the ninth level, all in a manner previously explained. When the wipers are raised to the ninth level, the shaft controlled springs 12%, are brought into engagement with each other by the operation of the shaft. This may be accomplished by any suitable cam arrangement. The springs are also shaft springs but they are adjusted to be shifted by the shaft when it is operated to the tenth level. The springs 1% are also operated on the tenth level. A convenient way to mount these springs is just above the top of the shaft so that the springs 124 may be actuated by the circular cup spring casing which is mounted at the upper extemity of the switch shaft. To proceed, the slow actingseries relay 54L is energized during the vertical movement of the switch and for an instant thereafter, and as before completes the circuit of the slow acting relay 59. On deenergizing, the relay 54 sends an impulse of current to the stepping magnet 252 of the minor switch J which operates to move the wipers 267 and 268 into their second position. i i hen the next digit 1 is sent by the subscriber at substation iii the line relay 52 operates as before and sends one impulse of current to the rotary magnet 12iin series with the slow acting relay 5%. ll/lagnet 12? operates to rotate the wipers 1354.38, inclusive, into engagement with the first set of contacts in the ninth level. Relay ill operates as before and completes the circuit of. the slow acting relay 59. It will be noticed that two test wipers and 13? are shown in the drawings each adapted to engage test contacts. in Fig. 7 one level of these test contacts are shown which we will assume represent the connections between the two sets of test contacts in the ninth level. It is assumed that in the case about to be described, there are a number of trunl: lines going to a manual exchange. The connector H must be able to select and connect with an idle one of these trunks or, if all should be busy,noti:ly the calling subscribed of this with the same results. Upon the subscriber at substation A operating his calling device in accordance with the digit 0, ten interruptions are thereby pl'OdllCtWl in the circuit of the line relay 52 which responds thereto sending ten impulses otf current to the vertical magnet 126 in series with the slow acting relay 54:. clays and 59 operate as be fore sending an impulse of current to the stepping magnet 25.). 'lhcvertical magnet 126 operates to step the wipers 135438, in elusive, opposite the tenth level oi bank contacts. Upon the tenth vertical step, the shatt controlled springs 12-11: and are shifted into their alternate position. hen the subscriber at substation A operates his calling device S in accordance with the next digit of his number. namely the digit 1, the line relay 51 operates in response thereto and sends one impulse oi current to the ro tary magnet 127. Slow acting relays 5i and 59 energize and it the trunk line with which the wipers are now in engagement busy, ground will be present on the test contacts thereol engaged by the test wipers 136 and 137. The connector H will operate as he :tore described to find an idle trunk or, it all trunks are busy going to this particular antomatic exchange, it will stop rotating on the contacts in which the last trunk line of a group is terminated. and transmit a busy signal to the calling subscriber at substation A. It will of course be understood that the test contacts of each group of trunk lines are connected in a mannersimilar hercinbetore described with regard to the ninth level. lilowcver, it will be assumed that the trunk line shown in the drawings comprising conductors 16%, 165 and 166 is idle. Under these condi ions, upon the test wipers 186 and 137 ei'iga'ging contacts 141 and 14.2 and no ground being present thereupon, the switching relay 56 will ei'iergize. All this occurs in a manner similar to that hereinbo'lore explained. hen relay 56 energizes, it establishes a locking circuit :tor itself at armature and at the sametime con'ipletcs a circuit extending from ground on release trunk conductor 81 by way of arn'iature 95, its tront contact, shaft cont-rolled springs 75, and thewinding of relay 50 to battery. Re lay .30 on energizing locks itself to ground on the release trunk conductor 92 and extends the line conductors 11 and 12 by way oi a rinaturcs (S5 and. G9 and their itront contacts, wipers 135 and 13S, bank contacts 141) and 143-3, conductors 164: and 166, norn'lally closed springs controlled by relay 325, and thence to the upper-and, lower wii'idii'igs ot' the line relay 3% which energizes completi ng the circuit of the slow release relay 327. Relay 327 energizes. removes battery from the release trunk condiurtor 165, and at armature 323i and its trout contact places ground (hereon, over which it llows by way of bank contact 142, test wiper 137, conductor 196, wiper 266, conductor 180, armature 66 and its front contact, front contact and armature (i7, winding of relay 50 to battery. This ground also extends back to the lincswitch C and hence maintains switches C and H in their operated position. It will be understood that the above traced holding is established betore the slow acting release relay 53 deenergizes. The subscriber may now operate his calling device in accordance with the tirst digit of the subscribers number in the distant automatic exchange. A series of interruptions produced in the circuit out the line relay 326. Relay 326 on operating in response to these impulses breaks the bridge across the trunk con" ductors 3&0 and 341 a corresponding number of times thereby repeating the impulses sent to the line relay of the switch in the distant exchange. This bridge across the trunk may be traced from trunk conductor 84:0, front contact and armature 333, ar nature 33stand its front contact, trout contact and armature 336, trunk conductor 3&1. The connection to the SilbSCI'lbGl in the dist-ant automatic exchange may now be completed in the ordinary manner.

It will be seen that this connector may have access to groups of trunks going to a number of manual and automatic exclninges and because two digits are sent to the connector it will be unnecessary to allot one level to one exchange.

Having fully described and ascertained the features of our invention what we con sider to be new and desire to have protected by Letters Patent will be pointed out in the appended claims.

that we claim as our invention is:

1. In a telephone system, a line, a coin nector switch, auxiliary switches individual thereto, means for establishing a connection with said line by means of said connector switch, code ringing mechanism, means for selectively operating two of said auxiliary switches in succession to select a particular code ring, and autol'natic means for operating another of said auxiliary switches to initiate the application ott said code ring to said line.

2. In a telephone system, a line, a conned tor switch, auxiliary switches individual thereto, a relay in said connector switch .ior applying ringing current to a called line, a code ringing interrupter, means for operating said connector to establish a connection with the said line, means for then selectively operating two of said auxiliary switches in succession to select a code, auton'iat-ic means for o nerating another of said. ai'ixiliary switches to prepare the circuit ot said relay, and means for variably energizing said relay by means of said interrupter to apply a code ring to said line.

circuit 3. In a telephone system, a line, a connector switch, auxiliary switches individual thereto, a relay 1n sald connector switch tor applying ringing current to a called line, a

code ringing interrupter, means for operating said connector to establish a connection with the said line, means for then operating two of said auxiliary switches to select a code, automatic means for operating another of said auxiliary switches to prepare the cir cuit of said relay, means for variably energizing said relay by means of said interrupt er to apply a code ring to said line, means ope "ative upon the called subscribe answering for cutting olt the ringing current trom said line, and means effective if the called subscriber removes his receiver during a code ringing period for rendering the -said -I'i1'1g cut oil means inoperative.

t. In a telephone system calling and walled subscribers, an auton'iatic connector switch. auxiliary switches individual thereto, a 1'elay in said connector switch for applying ringing current to a called line, means whereby one of the calling subscribers may establish a connection with a called subscriber by means of said connector switch, a code ringing interrupter, means for then operating one of. said auxiliary switches to select a code, automatic means for operating another of said auxiliary switches to prepare the circuit of said relay, means for variably energizing said relay by means of said interrupter to apply a code ring to said line. means under the control of said calling subscriber for releasing said connector switch, and means for rendering the said releasing means inoperative during a code ringing period.

5. I11 a code ringing machine, rows of variably positioned contacts, brushes cooperat ing with said rows, two directively controlled switches successively operated to select two of said brushes, a ringing relay and means for energizing it a plurality of times. the number of times depending on the brush selected by the first operated switch, a third switch and means tor operating it to shitt fill the control of said relay to the brush selected by the second operated switch. and means for then energizing said relay a pinrality of times under control of the said last brush.

6. In. telephone system, two classes ol subscribers lines, cut oil relays and private normal conductors associated with said lines. a connector. switch having banlt contacts in which the said conductors terminate, a pri vate wiper in said connector adapted to engage only the said contacts associated with the lines in one class. another private wiper in said connector adapted to engage only the said contacts associated with the lines in the other class, means for operating said connector to select a called line in either clas two kinds of ringing equipment associated with said connector, and means under control of said wipers for putting one or the other of said equipments in use depending on the class in which the called line belongs.

7. In a telephone system. two classes of subscribers lines. cut oil relay." and private normal ctmductors associated with said. lines, a connector switch having hank conta ts in which the said comluctors terminate. a private wiper in said connector adapted to en only the said contacts associated with the lines in one class. another private wiper in said connector adapted to engage only the said contacts associated with the lines in the other class, means tor operating said CODllQCl-Ol to select. a called line in either class, and means controlled over one of said wipers for signalling the called line immediately if said line belongs to one ol said classes and controlled over the other oil said wipers to signal the called line only after an interval ii said line belongs to the other of said classes.

8. In a telephone system. two classes ol subscribers lines. cut olt relays and private normal conductors associated. with the said lines, a connector switch having banh con-- tacts in which the said conductors terminate. a private wiper in said connector adapted to engage only the said contacts associated with the lines in one class, another pri rate wiper in said connector adapted to engage only the said contacts assmriated with the lines in the other class, means for operating said connector to select a called line in either class, and a switching relav in said connector energized at once over one of said wipers iii the called line belongs to one ol' said classes and energized after a time interval over the other oi. said wipers it the called line belongs to the other of said classes.

9. In a telephone system, private or individl'lal lines and party lines. an automatic connector switch responsive to the calling ot two digits in desired telephone numbers to select: de .ed ones of said lines. means for antmnatically completing the connection and tor signalling the called subscriber it the called line is a private line. means whcrcby the completion of the connection is de- :terred it the called line is a party line, code selecting mechanism responsive to another digit in the called number it the called line a party line. and means for automatically coi'npleting the coi'lnection when the proper code is selected and 'lor signalling the called subscriber in accordance with the selected code.

10. In a telephone system. two classes o'l lines, two digit telephone numbers assigned to the lines ot one class. tour digit numbers assigned to the lines in the other class. an automatic connector switch responsive to the calling out a two digit number to call a subscriber on a line in the l" st class and reti l llltl llll lilo

lit)

sponsive to the calling of a four digit number to call a subscriber on a line in the sec ond class, and ringing cquipn'ient automatically started in each case when the calling of the number is completed to signal the "alled subscriber.

11. In a telephone system, private or indivldual lines and party lines, an automatic connector switch, means wl'iereby a calling subscriber can operate said cminector in accordance with desired telephone numbers to connect with desired ones o't. said lines, and rii'iging equipn'ient auton'iatically responsive after two digits have been called to signal the called subscriber in case such subscriber has a private line, and automatially responsive after four digits have been called to signal the called subscriber in case such subscriber is on a party line.

1 In a telephone system, a trunk line extending to an automatic exchange, a trunk line extending to a manual exchange, a party line, an individual line, an automatic connector switch operable to establish connection with any one of said lines as a called line, means for closing a metallic connection through said connector in case the said auto matic trunk line is connected with to permit the transmission of operating lU'IDHlHQS, condensers includ'ed in the connection when any other line is connected with, means for transmitting signalling current over the manual trunk when the same is connected with, code ringing mechanism tor signalling a desired party on said party line when the said party line is connected with, and automatic intern'iittentringing equipment t'or signalling the party on .said individual line when connection thereto is established.

The con'ibination, with a ringing relay and an in'ipulse sender tor transi'nitting series of code impulses to said relay, ot a plurality of progre sively movable switches for registering digits in it called number, and a progressively movable sequence switch for placing said sender under the control. of said register switches succ ively.

1 t. The combiiuition,with a ringing relay, of a code ringing machine for operating said relay in accordance with two digit codes. said machine cmnprising a drum interrupter having two series otli contacts arranged in line, a brush for engaging all said contacts in successioi'i, a circuit including said relay and brusl'i, and means "for rcndering said circuit ei't'ectivc after said brush has engaged a variable number of contacts in the lirst series (it said contacts, and tor rei'idering said circuit inellj'ective ailitcr said brush has engaged a variable number ot contacts in the other series oi contacts.

15. The combination, with a ringing relay. of a code rii'iging machine for operating said relay in accori'lancc with two digit codes, said machine comprising a drum in terrupter having contacts, a brush for engaging all oi said contacts in succession, a circuit lI'iCltlCllIlg said relay and said brush, means for rendering said circuit effective after said brush has engaged a variable number of said contacts, and means for rendering said circuit inejtl'ective after said brush has engaged the desired number of said contacts while said circuit is etlective.

'16. In a telephone system, a party line connector having primary and secondary motor magnets, two auxiliary ringing cur-' rent selecting switches individual to said connector, each ringing switch having a motor magnet, a line relay in said connector, and another auxiliary switch individual to said connector for placing said magnets successively under the control of said relay.

1.7. In a telephone system, a party line connector having primary and secondary motor magnets, two auxiliary ringing current selecting switches individual to said connector, each ringing switch having a motor magnet, a line relay in said connector, another auxiliary witch individual to said connector 't'or placing said magnets successively under the control of said relay, a conductor over which the said line relay controls thesaid magnets, a motor magnet for said last mentioned switch, and a relay included in said conductor tor controlling said last mentioned magnet.

18. In a telephone system, a group oil? connectors, individual and party lines accessible to all said connectors, a common relay tor use by any connector in ringing ilulividual lines only. and an individual relay in iach connector for ringing party lines.

it). In a telephone system, a combined individual and party line connector, individual ringing equipment and party linev ring ing equipment associated with said connector, means automatically responsive to the completion oi. a connection with an indi-- vidual line for rendering the individual ringing equipment etl'ective, andv means auto- .niatically responsive to the completion of a connection with a party line for remleriug said, party line rii'igin'g equipn'ient eli'ective.

20. in a telephone sy tem, a combined individual and party line com'iector switch, said switch having facilities for performing ditl'erent characteristic rin ing OPQItltiUUS depending on the kind ot line cmmccted with, and. means in said switch automatically res ionsive when a line is comiectcd with tor determining the character of the ensuing ringing operation.

21. {in a telephone system, a combined individual and party line connector having two test wipers, imlividual and party lines acmrssible to said connectoi; private normal ronducmrs tor the individual lines terminating in the bank of one ol said wipers, and

ll U

private normal conductors for the party lines tcrn'iinating in the bank of the other oi said wipers.

22. In a telephone system, a combined individual and party line connector having two test wipers, individual and party lines accessible to said connector, a cut-oil relay for each individual line controlled by one of said wipers, and a cut-oil relay for each party line controlled by the other of said wipers. V

23. En a telephone system, a connector having a test wiper, a test relay, an auxiliary ringing current selecting switch indi vidual' to said connector, and a circuit for said relay including said test wiper, and a wiper of said selecting switch.

24. In a telephone S y'5t()l1'i, a connector switch for establishing connections with individual or party lines, said individual and party lilies promiscuously interspersed with respect to each other in the bank of said switch, said switch having 'tacilities tor performing diiterent characteristic ringing operations depending on the kind oi line connected with, and means in said switch automatically responsive when a line connected with for detern'iining the character of the ensuing ringing operation.

25. In a telephone system, an automatic switch, a party line, a plurality of signalling means, n'ieans for indicating the busy or idle condition of said line, means for first operating said switch to connect to said line, means "for then selecting any one of said signalling means, means for testing said line for the busy or idle condition, and means for maintaining said testing means disabled until after the selection of signalling means is completed.

26. In a telephone system, an automatic switch, an auxiliary switch associated with said automatic switch, a party line, a plurality of code signalling means, means for operating said automatic switch to connet to said line and for then operating said auxiliary switch to selectany one oi? said code signalling means, means for testing said line for busy or idle condition operable only v after operation of said auxiliary switch, and

means for starting the signalling operation when the selected signalling means reaches its starting position provided the said party line is idle.

27. In a telephone system, an automatic Switch, two auxiliary switches associated with said automatic switch, a party line, a plurality of signalling means, means for operating said automatic switch to connect to said line andlor then successively operating said auxiliary switches to select any one of said signalling means. means for testing said line, and means t'or delaying the testing of said line until after said auxiliary switches are operated.

28. In a telephone system, an automatic switch, a party line, a code ringing mechanism, means for operating said switch to connect with said line, means for selecting a code for signalling a desired party on said line, means for testing said line, and means for n'iaintaining said testing means disahlcd until the code is selected.

29. In a telephone system, signalling mechanism, a party line. means for connects ing with said line, a iirst and second register for registering two digits of the party line number, means including a wiper oi? said first register to start the sending o't signals over said line, and means including a wiper of said second register to stop the sending of signals over said line.

30. In a telephone system, a party line connector, signalling mechanism, a. lirst and a second register individual to said connector, means for setting said registers in accordance with two digits oi? a called line, means including a wiper of said first register for starting the sending ol signals. and means including a wiper ot' the second register itor stoppi. the sending of signals.

31. In a control system, an impulse sender, a first and a second register, means for set ting each register separately, means including a wiper of said first register for arting the sending of impulses, and means includ ing a wiper of said second register for stopping the sending oil impulses.

32. In a control system, an in'lpulsc sender, a first and second register, in ans :lor setting Said registers separately, means including a wiper oi said lirst register for starting the sending of a series of impulses in accordance with the setting of the first register. automatic means for starting the sending of a second series of impulses, and means including a wiper of said second register for step pingthe sending of said second series of impulses in accordance with the setting of the second register.

33. In a telephone system. a party line connector, a party line. means for operating said connector to connect with said line, a nailing mechanism. a first and second register, means for setting said registers in accordance with two digits, respcctiwly, of a. line number, means including a wiper of said first register for starting the sending of a first series o'l signals over said line in accordance with one oi said digits.automatic means for starting the sending ot a second series of signals over said line. and. means including a wiper of said second register for stopping the sending oil. said second series of signals in accordance with the other of said digits.

In a. code signalling machine, means for sending two spaced series of inujiulses. and means for arying the number of cllective impulses in each series while maintaiu- IUD ] ill ing the spacing between the series invariable, said means comprising a device for cancelling one or more impulses at the beginning of the first series and a second device for cancelling one or more impulses at the end of the second series.

2-35. In a telephone system, an automatic switch, a party line, means for operating said switch to connect with said party line, signalling selecting means operable in accordance with it plurelit of digits after said switch is operated, and means for testing said party line after said signalling selecting means is operated.

Signed by me at Chicago, 111., this 30th 15 day of November, 1920.

ARTHUR J. RAY. Signed by me at I-Iabana, Cuba, this 15th day of December, 1920.

FRED THORl/VALD MADSEN. Signed by me at Chicago, Illinois, this 30th day oi November, 1920.

HERBERT F. OBERGFELL. 

